Pathology is the study of disease. A pathologist is a medical doctor who looks at the causes of disease, how diseases progress, and how diseases affect the body.

However, instead of examining the patient physically, a pathologist examines body fluids and tissue samples from that patient to help the primary doctor make a diagnosis.

Most people have had blood and urine tests done during their lifetime. These tests are analyzed by pathologists to help determine the next step in a patient's treatment plan.

Lab tests of almost any nature are done to establish or confirm a diagnosis; rule out diagnoses; help determine a treatment plan; monitor a disease and how it responds to treatment; or screen for any underlying disease or risk factors.

Lab tests are done in both independent and hospital-associated labs, which are under direction of pathologists. Medical labs can be categorized as clinical pathology or anatomical pathology.

Clinical pathology is the study of diseases through evaluation of the body's biochemical processes, such as the production of hormones, enzymes, and other substances. Clinical pathologists analyze blood, urine, and other body fluids.

Anatomical pathology is the study of diseases by examining tissue samples obtained through surgery or an autopsy from specific parts of the body. Anatomical pathology helps determine the causes and effects of a particular disease.